Pointers and trackers for use on moving vehicles, particularly when installed on aircraft require multi-axis rotational capabilities. When pointers and trackers are installed on a moving, high-speed vehicle such as an aircraft, acquiring a target such as a star or any other distantly located target which is desired to be pointed toward and subsequently tracked, a real challenge is recognized which requires the coordination of research and development between many disciplinary scientific fields including chemistry, physics, engineering, metallurgy, ceramics, and including many other specializations within the broadly identified disciplinary fields.
The prior art systems having related design elements which include pistons and spider design are identified with the following programs: Airborne Pointer and Tracker (APT), Navy Pointer Tracker (NPT), and Airborne Optical Adjunct (AOA). It is recognized that the use of piston and spider designs have progressively improved with respect to more travel range in the fine drives region. For example, APT design used a piston and spider design which included a spherical head with a .+-.5 milliradian (mR) travel. NPT used a spherical head contacting at the piston center for .+-.10 milliradian travel. AOA used a cylindrical roller to achieve .+-.25 milliradian travel. The spider design refers to the spacial arrangement of flexure leaves in a four quadrant relationship to convert force to rotary motion of the spider.
The currently used AOA device employs a roller mechanism for the fine drive axes. Desirable is a device which will allow for larger travels and lower friction while producing a stiffer structural coupling between the actuator and the load.